DOCSLIB.ORG

Internal Forces and Their Influence on the Earth's Surface

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Internal Forces and Their Influence on the Earth's Surface EARTH SYSTEM: HISTORY AND NATURAL VARIABILITY – Vol. I - Internal Forces and Their Influence on the Earth’s Surface - Plašienka D. INTERNAL FORCES AND THEIR INFLUENCE ON THE EARTH'S SURFACE Plašienka D. Slovak Academy of Sciences, Bratislava, Slovakia Keywords: Earth’s mantle, convection currents, lithosphere, strength, plate tectonics, tectonic forces, stress in the lithosphere, deformation, earthquakes Contents 1. Introduction 2. The Earth’s Interior—Thermal and Compositional Structure 2.1. Internal Heat 2.2. Geospheres 3. The Mantle Engine 3.1. Short-Term Mantle Properties 3.2. Convective Flow Patterns 4. Rheology of the Lithosphere 4.1. Flow Conditions 4.2. Brittle Behavior 4.3. Ductile Behavior 4.4. Layered Lithosphere 5. Stress in the Lithosphere and its Relaxation 5.1. Forces and Stresses 5.2. Stress versus Strain 5.3. The Brittle Crust and Seismicity 6. Conclusion Acknowledgments Glossary Bibliography Biographical Sketch Summary UNESCO – EOLSS Earth works like a heat machine, in which heat is transported from its interior towards the surface. This is the principal way Earth cools. The internal thermal and gravitational instabilities vanish due to mass movements that transport heat by thermal convection, mainly within Earth’sSAMPLE mantle. Increasing temp CHAPTERSerature lowers the rock strength so that rocks in Earth’s interior are able to flow in a viscous manner. Convection currents in the mantle ultimately induce various kinds of deformation and movements of the Earth’s upper layers. The stiff outer shell of Earth, the lithosphere, has a different composition and properties in oceanic and continental areas. The oceanic lithosphere is relatively uniform and strong, while the continental lithosphere, and especially its crust, is weak due to compositional and rheological layering. Consequently, the continental crust is prone to extensive deformation expressed by mountain building and seismicity. ©Encyclopedia of Life Support Systems (EOLSS) EARTH SYSTEM: HISTORY AND NATURAL VARIABILITY – Vol. I - Internal Forces and Their Influence on the Earth’s Surface - Plašienka D. The system of driving and resistive forces produces various stress fields in the lithosphere. Provided the rock strength is overcome, the stress is relaxed by deformation. Faulting, folding, and ductile creep are the main processes by which crustal rocks are deformed. Ductile flow in deeper parts of the crust initiates stress amplification in the brittle upper crust that is transiently relieved by seismic slipping along active faults, generating sometimes catastrophic earthquakes. 1. Introduction Earth’s surface, on which humankind lives, exhibits an endless variability in morphological forms. The continental exteriors vary from mountain belts and volcanic chains to hilly areas and flat lowlands, the oceanic bottom rises from large abyssal plains to seamounts and ridges and falls to narrow trenches. All this variability is an expression of the ever-present competition of two classes of energetic sources. The first class is the heat production in Earth’s interior that generates forces known in geology as internal or endogenous. The internal forces drive all the vertical and horizontal movements of Earth’s crust and are responsible for some severe disasters such as earthquakes or volcanic eruptions. The second class—the external or exogenous forces—is generated by energetic input from the Sun. They trigger motions in Earth’s hydrosphere and atmosphere and tend, through weathering, erosion, and sedimentation, to decrease the morphological expressiveness created by internal forces. This is an expression of the second theorem of thermodynamics predicting dissipative exchange of energy between systems that are in mutual disequilibrium. Generally, if there were no atmosphere and hydrosphere on Earth, the internal forces would produce extremely rugged surface morphology with any kind of steep positive or negative forms that could sustain gravitational forces. On the other hand, if there were no internal forces, erosion would quickly diminish all morphological variations and Earth would become a boringly flat spheroid body. The purpose of this article is to outline how the internal forces are generated, distributed, and dissipated, and how they influence the composition, structure, movements, and deformation within the upper layers of the solid Earth. 2. The Earth’s Interior—Thermal and Compositional Structure UNESCO – EOLSS 2.1. Internal Heat The degree of surface instability of every planet in the Solar System is proportional to its internal mobilitySAMPLE (i.e., to the ability of masses CHAPTERS in the planetary interiors to move due to accommodation of thermal and gravitational instabilities). This can be expressed by the ratio of volume (V) to the surface area (S) as being proportional to radius (R) in the equation: V 4 π R 3 R = 3 = S 4π R 2 3 This means that this ratio is high for large planets and they cool slowly due to their smaller surface area per volume compared to small planets and moons, which have a ©Encyclopedia of Life Support Systems (EOLSS) EARTH SYSTEM: HISTORY AND NATURAL VARIABILITY – Vol. I - Internal Forces and Their Influence on the Earth’s Surface - Plašienka D. comparatively low heat capacity and a large surface area per volume to cool out. Accordingly, large planets are hot and mobile, depending on their compositions. Among the terrestrial planets composed mostly of silicates, only those with large radii are able to store enough thermal energy to reduce the strength of rock masses in their interiors. Increasing temperature lowers the rock strength exponentially and every rock begins to flow at a certain temperature. This holds for Earth and Venus in particular, which are hot enough for their interiors to be highly mobile. In the case of Earth, the internal thermal and, consequently, gravitational instabilities vanish due to mass movements that are transferred towards the surface and expressed by various kinds of deformation and movements of the upper, seemingly stiff layers of Earth. Accordingly, Earth may be regarded as a heat engine, though Earth’s internal thermal input power is rather low (approximately 1 × 107 MW, which is comparable to the energetic production of the whole of humankind). The principal sources of internal heat are considered to be twofold: (1) the heat inherited from the early accretionary period of Earth and (2) the radiogenic heat produced by decay of radioactive elements presently involved in Earth’s crust and mantle. During the earliest stages of Earth’s history (some 4.7–4.5 billion years ago), its internal heat rose gradually, being generated by transformation of the kinetic energy of incident particles forming the early Earth and by the thermal energy released during the gravitational collapse, adiabatic compression and an increase of the density of Earth’s body. Later on, the temperature in Earth’s interiors reached the melting point, which enabled the gravitational differentiation of rock masses producing additional heat. However, the radiogenic heat production has been the most important input power during the whole of Earth’s history. It is generated by the breakdown of radioactive isotopes, which had originally been randomly distributed within the early Earth’s body but, being comparatively light, became concentrated in Earth’s upper layers after the gravitational differentiation. (See Early Earth). Earth’s body is thermally inhomogeneous. The temperature in its core reaches 6000 °C, while the surface temperature approaches 0 °C. Obviously the temperature increases with depth. This downward increase (directed to Earth’s center) is known as the geothermal gradient, a measure of rise in temperature per unit length. Surface and subsurface measurements in deep wells and mines indicate this gradient to be in the range of 10–40UNESCO °C km–1, most typically 20–25 – °CEOLSS km–1. However, an extrapolation of this value to Earth’s interiors would mean unrealistically high temperatures, therefore the thermal gradient has to decrease with depth. This is in line with the observation that the radioactive elements as the main sources of Earth’s heat production are concentrated in the crust. Nevertheless,SAMPLE Earth is hottest in itsCHAPTERS center and coldest on its surface, which indicates that a great deal of its thermal energy is being dissipated on the surface. In fact, this and other losses only slightly exceed the internal heat production, which means that the Earth as a whole cools very slowly, negligibly with respect to the length of human existence. Variations in the near-surface geothermal gradient are an expression of a changing heat flow, a measure of the thermal input from Earth’s interiors towards its surface. The heat flow density indicates the amount of heat that is released from Earth’s surface per unit area and per unit time. Within Earth’s body, the heat is transported in two principal ©Encyclopedia of Life Support Systems (EOLSS) EARTH SYSTEM: HISTORY AND NATURAL VARIABILITY – Vol. I - Internal Forces and Their Influence on the Earth’s Surface - Plašienka D. ways—by conduction and convection. Thermal conduction differs for various rocks, and prevails in the stiff upper layers of Earth. Thermal convection means heat transport by moving matter, and prevails in Earth’s interior. However, many large positive heat flow anomalies on Earth’s surface are dominantly produced by thermal convection, for example by ascending magmatic melts or aqueous and other fluids in active volcanic areas. But also in nonvolcanic areas with thinned crust, which are usually overlain by large and deep sedimentary basins, the heat primarily conveyed from the depths by conduction is then distributed by meteoric waters circulating within the upper crustal rocks. Geothermal energy might be, thanks to its apparent inexhaustibility, one of the most important energy sources for humankind in the future. Nowadays, this energy is only widely utilized in certain areas with high heat flow, to produce electric power and to heat various objects such as buildings or greenhouses. However, the energetic potential of areas with normal and even with lowered heat flow is considerable as well.
Load more

Recommended publications
  • Lecture 2A Structure and Composition of the Earth Plate Tectonics
    Engineering and Environmental Geology (EART 3012) – 2014 Lecture 2A Structure and composition of the Earth Plate tectonics Dr Tom Raimondo See Marshak pg. 42–53; 78–100 Figures taken from Earth: Portrait of a Planet, WW Norton & Co. Course outline and introduction Sweet weekly homework Every week, there are regular tasks that must be completed. There are clear expectations about the amount of time you should spend studying this course. Contact time per Non-contact time per week week Lectures 2 hours 1–2 hours pre- reading and revision Practicals 2 hours 1 hour pre-reading Weekly quizzes - 30 mins to 1 hour eModules - 30 mins to 1 hour Textbook online - 30 mins to 1 hour resources Total 4 hours 4–5 hours Lecture 2A Why do I need to know all this stuff? . Knowing the structure and composition of the Earth forms the basis for all geological concepts . We need to have a understanding of how the Earth behaves as a whole, and what its properties are, before we can consider more specific Earth systems and cycles . Plate tectonics is the fundamental geological theory for how the Earth works and how we can predict its behaviour . We need to understand this theory to be able to understand and interpret a range of geological phenomena (e.g. earthquakes, volcanoes, tsunamis, landslides, etc.) Lecture 2A Lecture outline Part 1: Structure and composition of the Earth . Layers of the Earth: crust, mantle and core . Lithosphere and asthenosphere Part 2: Plate tectonics . What is a tectonic plate? . Types of plate boundaries . Other plate features .
    [Show full text]
  • Earth's Interior
    11/7/2012 Please do the Audio Setup Wizard ! 11/7/12 Science Class Connect with Mrs. McFarland & Mr. Gluckin Earth’s Interior Ohio Academic Content Standards Today’s Class Agenda • Review Ground Rules for Earth and Space Sciences Classes The Universe • Earth’s Stats 9. Describe the interior structure of Earth and the Earth’s crust as • Composition of the Earth divided into tectonic plates riding on top of the slow moving currents of magma in the mantle. – Crust/Mantle/Core 11. Use models to analyze the size and shape of Earth, its surface and • Structures of the Earth its interior (e.g. globes, topographic maps and satellite images). – Lithosphere/Asthenosphere • Lithospheric Plates The Study Island lesson is due by 4pm on Thursday: SI 2e • State of matter and heat Student Centered Objectives – Convection Currents I will be able to describe the layers on the inside of the Earth. • Reminders I will be able use images to look at the Earth’s interior by composition. • Today’s Slides I will understand the different physical properties of the Earth’s layers. • Exit Ticket • Your Questions Ground rules Earth’s Stats • Please close all other apps & web pages. No Facebook, games, music, etc. • The Earth's mass is about 5.98 x 1024 kg. • No off‐topic chat • Be respectful of each other • Don’t share personal information • Earth is the densest planet in our Solar • I can see all chat … even “private chat” System (mass/volume). • Earth is made of several layers with different compositions and physical properties, like temperature, density, and the viscosity (“aka” ability to flow).
    [Show full text]
  • Earth's Structure and Processes 8-3 the Student Will Demonstrate An
    Earth’s Structure and Processes 8-3 The student will demonstrate an understanding of materials that determine the structure of Earth and the processes that have altered this structure. (Earth Science) 8-3.1 Summarize the three layers of Earth – crust, mantle, and core – on the basis of relative position, density, and composition. Taxonomy level: 2.4-B Understand Conceptual Knowledge Previous/future knowledge: Students in 3rd grade (3-3.5, 3-3.6) focused on Earth’s surface features, water, and land. In 5th grade (5-3.2), students illustrated Earth’s ocean floor. The physical property of density was introduced in 7th grade (7-5.9). Students have not been introduced to areas of Earth below the surface. Further study into Earth’s internal structure based on internal heat and gravitational energy is part of the content of high school Earth Science (ES-3.2). It is essential for students to know that Earth has layers that have specific conditions and composition. Layer Relative Position Density Composition Crust Outermost layer; thinnest Least dense layer overall; Solid rock – mostly under the ocean, thickest Oceanic crust (basalt) is silicon and oxygen under continents; crust & more dense than Oceanic crust - basalt; top of mantle called the continental crust (granite) Continental crust - granite lithosphere Mantle Middle layer, thickest Density increases with Hot softened rock; layer; top portion called depth because of contains iron and the asthenosphere increasing pressure magnesium Core Inner layer; consists of Heaviest material; most Mostly iron and nickel; two parts – outer core and dense layer outer core – slow flowing inner core liquid, inner core - solid It is not essential for students to know specific depths or temperatures of the layers.
    [Show full text]
  • Clay Model Earth
    Teacher Instructions Clay Model Earth Overview: During this lesson students will learn about Earth’s layers by making a clay model. As a result of this activity, students develop an understanding of the structure of Earth’s layers, particularly as it relates to thickness and solid or molten state. Students keep completed Earth models in the classroom for future reference during Units 2 and 3. Note: You may wish to build a sample model Earth in the classroom, then have students build models as a homework assignment. Objectives: The student will learn: • to identify Earth’s layers, including the inner core, outer core, mantle, and crust; • the relative size and thickness of each Earth layer; • that Earth’s inner core is solid due to tremendous pressure; and • that Earth’s outer core is molten, and exists in a “liquid” state. Materials: • Clay in the colors and amounts described in the activity procedure (see Note, following page) • Marbles (25 mm) for each student • Sharp knife • Ruler • Teacher Information Sheet: “The Thickness and State of Earth’s Layers” • Transparency: “Earth’s Layers” • Transparency: “Clay Model Earth” • Student Worksheet: “Clay Model Earth” Answers to Student Worksheet: Crust 1. refer to diagram 2. outer core Mantle 3. mantle Molten 4. crust outer core 5. This is a critical thinking question; answers will vary. Solid inner core Ola Ka Honua: Volcanoes Alive 43 ©2001, 2007 UAF Geophysical Institute Teacher Instructions Clay Model Earth Activity Procedure: 1. Give a 25 mm marble and the following amounts of each color clay to each student: • One 4 oz.
    [Show full text]
  • High School - Earth and Space Science
    High School - Earth and Space Science Grade Big Idea Essential Questions Concepts Competencies Vocabulary 2002 SAS Assessment Standards Standards Anchor Eligible Content The universe is What is the universe and The Milky Way Galaxy consists of Use models to describe the Clusters 3.4.10.D 3.3.10.B1 composed of a variety what is Earth’s place in more than two hundred billion sun’s place in space in relation Galaxy of different objects that it? stars, the sun being one of them, to the Milky Way Galaxy and the Model are organized into and is one of hundreds of billions distribution of galaxy clusters in Star 9-12 systems each of which of galaxies in the known universe. the universe. Universe develops according to accepted physical processes and laws. The universe is What is the universe and Models of the formation and Compare time periods in history, Geocentric 3.1.12.E 3.4.10.B composed of a variety what is Earth’s place in structure of the universe have the technology available at that Heliocentric 3.4.10.D3 of different objects that it? changed over time as technologies time and the resulting model of Model are organized into have become more advanced and the organization of our solar Planet 9-12 systems each of which the accuracy of our data has system. (e.g. – Early Greeks Theory develops according to increased. used purely observational data accepted physical resulting in a geocentric model). processes and laws. The universe is What is the universe and The Milky Way Galaxy consists of Use data about the expansion, Clusters 3.4.10.D 3.3.10.B1 composed of a variety what is Earth’s place in more than two hundred billion scale and age of the universe to Galaxy 3.3.12.B2 of different objects that it? stars, the sun being one of them, explain the Big Bang theory as a Light year are organized into and is one of hundreds of billions model for the origin of the Model 9-12 systems each of which of galaxies in the known universe.
    [Show full text]
  • Framework and NGSS
    POPULATIONS AND ECOSYSTEMS – Framework and NGSS INTRODUCTION TO Contents PERFORMANCE EXPECTATIONS Introduction to Performance “The NGSS are standards or goals, that reflect what a student Expectations .......................... 35 should know and be able to do; they do not dictate the manner or methods by which the standards are taught. Curriculum FOSS Conceptual and assessment must be developed in a way that builds students’ Framework ............................ 48 knowledge and ability toward the PEs [performance expectations]” Background for the (Next Generation Science Standards, 2013, page xiv). Conceptual Framework .......... 50 This chapter shows how the NGSS Performance Expectations are Connections to NGSS by bundled in the Populations and Ecosystems Course to provide Investigation .......................... 56 a coherent set of instructional materials for teaching and learning. This chapter also provides details about how this FOSS course Recommended FOSS Next fits into the matrix of the FOSS Program (page 49). Each FOSS Generation K–8 Scope and module K–5 and middle school course 6–8 has a functional role Sequence ............................... 74 in the FOSS conceptual frameworks that were developed based on a decade of research on science education and the influence of A Framework for K–12 Science Education (2012) and Next Generation Science Standards (NGSS, 2013). The FOSS curriculum provides a coherent vision of science teaching and learning in the three ways described by the The NGSS Performance Expectations NRC Framework. First, FOSS is designed around learning as bundled in this course include a developmental progression, providing experiences that allow students to continually build on their initial notions and develop Life Sciences more complex science and engineering knowledge.
    [Show full text]
  • An Introduction to Geology Focus on Concepts Each Statement Represents the Primary Learning Objective for the Corresponding Major Heading Within the Chapter
    1An Introduction to Geology FOCUS ON CONCEPTS Each statement represents the primary learning objective for the corresponding major heading within the chapter. After you complete the chapter, you should be able to: 1.1 Distinguish between physical and historical geology and describe the connections between people and geology. 1.2 Summarize early and modern views on how change occurs on Earth and relate them to the prevailing ideas about the age of Earth. 1.3 Discuss the nature of scientific inquiry, including the construction of hypotheses and the development of theories. 1.4 List and describe Earth’s four major spheres. Define system and explain why Earth is considered to be a system. 1.5 Outline the stages in the formation of our solar system. 1.6 Describe Earth’s internal structure. 1.7 Sketch, label, and explain the rock cycle. 1.8 List and describe the major features of the continents and ocean basins. All four of Earth’s spheres are represented in this image in the Canadian Rockies of British Columbia. (Photo by CCOphotostock_KMN) 2 M01_TARB6622_13_SE_C01.indd 2 11/11/16 12:55 PM 2 M01_TARB6622_13_SE_C01.indd 3 11/11/16 12:55 PM THE SPECTACULAR ERUPTION OF A VOLCANO, the terror brought by an earth- quake, the magnificent scenery of a mountain range, and the destruction created by a landslide or flood are all subjects for a geologist. The study of geology deals with many fascinating and practical questions about our physical environment. What forces produce mountains? When will the next major earthquake occur in California? What are ice ages like, and will there be another? How were ore deposits formed? Where should we search for water? Will plentiful oil be found if a well is drilled in a particular location? Geologists seek to answer these and many other questions about Earth, its history, and its resources.
    [Show full text]
  • Classroom Assessment Design
    HO1 Classroom Assessment Design Design What is it? How does NGSS help me How do I use it? Guidelines think about it? Performance • States what Reminds me that PEs Expectaons students should integrate the three Tool 1 know and be able to dimensions: SEPs, DCIs, CCCs do. Evidence of • Specificaons for Helps me describe an Learning the evidence that assessment(s) that integrates Tool 2 Provide the Specificaons students have the three dimensions within foundation for achieved and/or the PE(s). the assessment surpassed the PE. task The evidence is obtained through observaons of students and/or student work products. Assessment • The Assessment Task requires students to Task and demonstrate that they have achieved and/or Tool 5 Rubric surpassed the PEs by performing or producing student work aligned to the Evidence of Learning Specificaons Copyright © AMNH 2016 Page 1 Five Tools and Processes for NGSS Tool 2 HO2 Tool 1 Template Example – Unit Blueprint for MS-LS2 (Ecosystems: Interactions, Energy, and Dynamics) Instructional Sequence 1 Instructional Sequence 2 Instructional Sequence 3 Instructional Sequence 4 Instructional Sequence 5 Performance Expectation MS-LS2-2 Performance Expectation MS-LS2-3 Performance Expectation MS-LS2-1 Performance Expectation MS-LS2-4 Performance Expectation MS-LS2-5 Construct an explanation that predicts patterns of Develop a model to describe the cycling of matter and Analyze and interpret data to provide evidence for Construct an argument supported by empirical Evaluate competing design solutions for maintaining interactions among organisms across multiple flow of energy among living and non-living parts of an the effects of resources availability on organisms and evidence that changes to physical or biological biodiversity and ecosystems services.* ecosystems ecosystem.
    [Show full text]
  • Plate Tectonics - Martin Meschede
    GEOLOGY – Vol. I - Plate Tectonics - Martin Meschede PLATE TECTONICS Martin Meschede Institut für Geologische Wissenschaften, Universität Greifswald, Germany Keywords: plate tectonics, plate margin, hot spot, lithosphere Contents 1. Introduction 2. The Earth´s Composition 3. Age and magnetization of the Earth´s crust 4. Plates 5. Geometric Constraints 6. Plate Boundaries 6.1. Divergent Plate Boundaries 6.2. Convergent Plate Boundaries 6.2.1. Accretion and Subduction Erosion 6.2.2. Types of Plate Convergence 6.2.3. Oceanic-Oceanic Convergence 6.2.4. Continental-Oceanic Convergence 6.2.5. Continental-Continental Convergence 6.3. Conservative Plate Boundaries 6.4. Triple Junctions 7. Hot Spots Glossary Bibliography Biographical Sketch Summary The Earth is composed of layers of different composition and physical properties: the core, the mantle, and the crust. Two different types of crust exist, the thick and older continental crust and the thin and younger oceanic crust. Horizontal movements within the rigid crust are expressed by the concept of seafloor spreading which is based on magnetic anomaly patterns on oceanic crust as a result of repeated reversals of the Earth´s magneticUNESCO field. This concept is part– of EOLSSthe plate tectonic theory which describes the dynamic formation of new oceanic crust at mid-oceanic ridges, the subduction and destruction of oceanicSAMPLE crust at convergent plate CHAPTERS boundaries, the collision of continental plates and formation of mountain ranges, and the conservative movement of plates past each other along transform faults. Hot spots are thought to be stationary points with high volcanic activity which may reflect the plate movement by producing hot spot tracks at the surface when the plate moves over it.
    [Show full text]
  • Chapter 3: Atmosphere
    UO2-MSS05_G6_IN 8/17/04 4:13 PM Page 74 HowHow AreAre BatsBats && TornadoesTornadoes Connected?Connected? 74 (background)A.T. Willett/Image Bank/Getty Images, (b)Stephen Dalton/Animals Animals UO2-MSS05_G6_IN 8/17/04 4:13 PM Page 75 ats are able to find food and avoid obstacles without using their vision.They do this Bby producing high-frequency sound waves which bounce off objects and return to the bat.From these echoes,the bat is able to locate obstacles and prey.This process is called echolocation.If the reflected waves have a higher frequency than the emitted waves,the bat senses the object is getting closer.If the reflected waves have a lower frequency,the object is moving away.This change in frequency is called the Doppler effect.Like echolocation,sonar technology uses sound waves and the Doppler effect to determine the position and motion of objects.Doppler radar also uses the Doppler effect,but with radar waves instead of sound waves.Higher frequency waves indicate if an object,such as a storm,is coming closer,while lower frequencies indicate if it is moving away.Meteorologists use frequency shifts indicated by Doppler radar to detect the formation of tornadoes and to predict where they will strike. The assessed Indiana objective appears in blue. To find project ideas and resources,visit in6.msscience.com/unit_project. Projects include: • Technology Predict and track the weather of a city in a different part of the world, and compare it to your local weather pattern. 6.3.5, 6.3.9, 6.3.11, 6.3.12 • Career Explore weather-related careers while investigating different types of storms.
    [Show full text]
  • Role of Earth's Mantle in Water and Gases in the Environment
    Role of Earth's Mantle in Water and Gases in the Environment Term Paper Amir Salaree1 Earth315: Geochemistry of Global Environments Professor A. Lerman2 Abstract Earth’s mantle plays an important role in the material present in the environment and can be considered as the major contributors to the material found on the surface of the planet. This contribution was made essentially during the formation of Earth between 4.56 to 3 billion years ago while it accreted by drowning the heavier material and keeping the lighter components on the surface forming continents and initial ocean beds. However, today this contribution is in the form of degassing processes and tectonic procedures (such as mid-oceanic ridges spreading and volcanic eruptions) through which gasses and water and carbon are transmitted to the environment. These materials are usually kept in Earth’s mantle from earlier at its birth and are transmitted into it through tectonic processes like subduction. In this study, I have considered the basics of these processes. Through this work, some of the basic theories and concepts which are essential for a basic understanding of the subject are presented and are finally accompanied by some numerical figures as a demonstration of how the studied system works. Also some evidence are mentioned to support the general ideas which are referenced alphabetically at the end of the paper. 1 Introduction The Earth as we know today was formed 4.55 ± 0.07 × 109 years ago (Patterson, 1956) from the solar nebula. Patterson (1956) in his famous paper estimated the age of the planet using radiometric dating of meteorites (carbonaceous chondrites) considering lead isotopes (Fig.
    [Show full text]
  • Subject - Science: Science
    Subject - Science: Science Course - ESS: Earth and Space Science Section - ESS: Knowledge and Skills Strand - ESS: Solid Earth. Knowledge & Skill Statement - ESS.9: The student knows Earth's interior is differentiated chemically, physically, and thermally. The student is expected to: Student Expectation ESS.9A: Evaluate heat transfer through Earth's subsystems by radiation, convection, and conduction and include its role in plate tectonics, volcanism, ocean circulation, weather, and climate. ESS.9B: Examine the chemical, physical, and thermal structure of Earth's crust, mantle, and core, including the lithosphere and asthenosphere. ESS.9C: Explain how scientists use geophysical methods such as seismic wave analysis, gravity, and magnetism to interpret Earth's structure. ESS.9D: Describe the formation and structure of Earth's magnetic field, including its interaction with charged solar particles to form the Van Allen belts and auroras. Knowledge & Skill Statement - ESS.10: The student knows that plate tectonics is the global mechanism for major geologic processes and that heat transfer, governed by the principles of thermodynamics, is the driving force. The student is expected to: Student Expectation ESS.10A: Investigate how new conceptual interpretations of data and innovative geophysical technologies led to the current theory of plate tectonics. ESS.10B: Describe how heat and rock composition affect density within Earth's interior and how density influences the development and motion of Earth's tectonic plates. ESS.10C: Explain how plate tectonics accounts for geologic processes and features, including sea floor spreading, ocean ridges and rift valleys, subduction zones, earthquakes, volcanoes, mountain ranges, hot spots, and hydrothermal vents. ESS.10D: Calculate the motion history of tectonic plates using equations relating rate, time, and distance to predict future motions, locations, and resulting geologic features.
    [Show full text]